1. Field of the Invention
The invention relates to a tube, and to a golf club using a tube in accordance with the present invention.
2. Description of the Prior Art
Tubes are known which are manufactured through drawing of metal or through winding of mats of fiber-reinforced epoxy resin materials or through winding of fibers. These tubes are relatively light, but have a rather moderate bending elasticity. The tubes have poor oscillation damping properties. The damping properties must be improved subsequently through the installation or attachment of damping elements. All these tubes have insufficient damping properties for certain uses.
Conventional shafts of golf clubs are also e.g. either drawn metal tubes or tubes which are wound from fiber materials. Metal tubes are distinguished by good elasticity, but have however a relatively high weight and poor damping properties. Wound tubes of fiber materials are distinguished by low weight in the presence of moderate elasticity; the damping properties are however insufficient for many uses. The damping properties of tubes of fiber materials manufactured by a conventional method, such as drawing or winding, are hardly sufficient and must therefore be built in subsequently.
An object of the present invention is to create a tube of high elasticity, good torsion behavior and low weight. At the same time the tube should have good oscillation damping properties. It is furthermore an object of the present invention to create a golf club with a shaft which has high elasticity, good torsion stiffness and low weight.
A tube in accordance with the invention can for example be manufactured as follows. A first fiber layer is wound onto a winding body such as, for instance, a winding spike. This can take place with a winding machine which winds the threads or fibers one next to the other or which winds each winding at a specific distance from the next one on the winding spike. This first winding layer or wound layer respectively can be coated and impregnated with an epoxy resin. Then the longitudinal wires can be applied to the wound layer. The longitudinal wires can in turn be coated with epoxy resin and be embedded in the latter. The longitudinal wires together with the epoxy resin lying between them can thus form a longitudinal wire layer. Over the longitudinal wires further wound layers and onto these longitudinal wires can again be applied until the tube has the correct construction. If an only loosely wound layer lies over a wire layer and further wires are laid onto this loosely wound layer in such a manner that the wires of the second layer of longitudinal wires lie between those of the first layer of longitudinal wires, the longitudinally extending wires of the first and the second layer can be combined to a layer with a further, hard wound layer. The loosely wound layer then extends in wave shape about the longitudinally extending wires of this combined layer. The loosely wound layer can alternately extend over the one wire and under the next, adjacent wire. It is however also conceivable that the loosely wound layer extends over and under more than one adjacent longitudinal wire. A large number of structures are conceivable here.
The wires or the fibers for the tube can for example consist of metal, carbon fiber, glass of kevlar. The wires can be individual wires, but the construction of these wires can also be stranded, woven, cable-like, or the wire can be a braid. For example wires such as are used for piano strings are well suited. It is also conceivable to use wired of different materials and/or with different construction in one tube. The wires themselves can in turn be designed in tube or tubelet shape. The wires advantageously have a diameter of approximately 0.2 mm to 0.5 mm, with wires of other diameters naturally also being suitable.
The tube in accordance with the invention has the required properties such as high elasticity and high torsion strength at low weight which are for example necessary for the shaft of a golf club. Moreover, the oscillation damping properties can when required be varied with simple means and measures by installing or applying damping elements at specific positions. Foam materials are suitable as damping elements. In the interior of the tube for example a granulate of elastomer, such as latex, can be used. The granulate can be embedded in a foam material.
The tube in accordance with the invention is extremely resistant to bending and buckling, and thus has a good bending resistance strength. Moreover, the tube has very good tensile strength properties.